Etherpunk

Like I said before, I really dislike try/catches. They slow your code down and they are generally used when you don't know how to appropriatly handle data. For example, using try/catch to convert a string to an int versus using Int32.TryParse(). Yes, I've really seen this on the wild... and not from an amatuer either. I'll openly admit, I'm an OK programmer. I have much to learn. I just learned how to implement Transactions in code. I have learned how to make .NET crash so hard -- it throws an exception *outside* of your applications domain. This means you can't catch it. At all. But I'll get to that in a minute. I'd like to start by explaining when it's a good idea to use a try/catch.

Using try/catches are a good when you can't calculate everything. For example, network issues. Sure -- you can ping a server. Doesn't mean the database is up. Sure, you can do many other things such as test the database (SELECT 0 comes to mind) however you can't calculate the network being dropping in the middle of everything. So far the only method I've found that is reliable is using a try/catch because the medium is so volatile, even after doing your check it can go down. So, the answer is to use a transaction (if you are doing multiple inserts) and using a try/catch looking for a SqlException. But this won't stop everything... I'll explain how I pissed off .NET with pictures and network failures.

Apaprently .NET handles System.Image in an intersting way. It is only a pointer/reference to the location of the file. What this means is that if you reference an image across the network and it goes down -- System.Image throws an exception. In fact it throws a pretty gnarly exception that you can't catch. Here is how you can reproduce this. Create a blank project. Drop in a timer and set the interval to 15 second or an amount that a little longer than it will take you to unplug your network cable. Modify the form load to engage the timer and have the form load the image. Have the form hide itself. On the timer tick, have the form display itself (this will cause the image to be repointed and thus having to look at the network to pull the image). Start the app and then unplug your network cable. It should have a nasty crash. One you can't stop. Another thing I learned is that it puts a lock on the file so you can't delete/modify it. So far the only idea I've come up with to have an in-memory cache is to load it in to a byte array from a stream and have you rference that byte array. What I don't know is if it's still a pointer to the file. I might assume that that stream will push the bits in to the byte array and thusly remove the dependance of the network.

Using SubSonic the code to implement transactions and SqlException is pretty straight foreward and you would just surround your .Saves (personally, I like to place everything in the try/catch block just to make the code look cleaner) with a System.Transactions.TransactionScope. A TransactionScope will put a lock on your table when doing an insert, and for good reason. This is because you can't rely on the data to be inserted until you do a commit. So this will stop people from seeing the data (or any in the table for that matter) so they don't reference it and then have the transaction cancelled and then you have an inconsistant database. If you want a way around that then you should use System.Transactions.TransactionOptions. TO has only two properties -- timeout and the scope options. Microsoft has an article explaining the enumerations and their values and which ones you would want to use for which circumstances. I should probably link it but I'm too lazy.

I'm in the process of getting an app going under .NET 3.0 using Visual Studio 2008 to see the differences in speed between Linq, SubSonic, and using a plain SQLDataAdapter. Yes, I'm well aware using a DataReader / DataAdapter is going to be faster -- the question is: How much faster? Is it worth making the code that much more cleaner? What about if the code is only going to be used once 4 months from now and, hopefully, never touched again? My problem is I want something to be as fast as possible without making code ugly and without spending a lot of time tweaking -- so I'm taking the shotgun approach. At the moment, it seems like they are all fairly close unless you are dealing with LOTS (millions) of records -- which I am not. SubSonic has its fair share of bugs such as puking if a table doesn't have a primary key. I can understand it not understanding how to right back or do complex queries, I just want to populate a collection with a 'Select *' type statement -- so it doesn't need a care about primary keys as I'm just going to loop through item in the collection and pull data as I see fit. Also, SubSonic seems to always do a 'SELECT *' type query if I want to use the simple code such as 'Some_DB.Some_TableCollection TC = new Some_DB.Some_TableCollection().Load();'. If I want to be specific then I have to use a Query class. Even worse, it's /horrible/ at doing OR's. They really prefer you to use views or stored procedures. Neither of those are bad, but I'm not writing code for something anyone else but me should be using -- so I don't care about exploits or any safety measures. Even if I was, this engine doesn't have any direct input mechanism, so good luck with that. Linq seems overly complicated. Fucking A is it a bitch to setup. Nothing seems automatic. Code doesn't /feel/ cleaner (so far from my, admittedly, little testing). Google doesn't seem to know how to use it either. I'm finding contradicting information. So, this means I have to do a "best case scenario" speed test to get both Linq and SubSonic working, which isn't a bad idea. One of the programming styles I learned was "assume everything will work perfectly, *then* make exceptions". The alternative, which is more common, is plan for the worst then if it's the best do X. The problem with that is you are always occurring the overhead of the worst instead of doing the best first and if it fails (Which it rarely should) then go to some exception handling. This places me back at square 1. Here is my game plan:

• Have a script which will populate a database + table with random data. This way nothing can be cached and you can regen as needed. This will probably populate a 'person' table with 2 million records. This is a small amount compared to some other databases, but for our instance it should be plenty to test for speed.
• Write a GUI which has a listbox and a DataGridView. The listbox will contain different methods of getting data from a SQLServer to a DataGridView. The hope being that if I can get it from a SQLServer to a DGV then I can be fairly certain nothing got cached and everything got pulled over for data manipulation.
• Write a a few tests. These tests will probably be a simple SubSonic, Linq, and SQLDataAdapter. I will later do more complex queries and embed them to attempt to bring out slowness or resource hogs. SQDA and SubSonic will be the first two. Linq will be third, and any other complex queries will be last.
• Open source the program and release to world under BSD license.

I'm also probably going to try some of this code on other DB engines such as MySQL and SQLite.